Actuating mechanism for seat restraint divestment system

ABSTRACT

A mechanism for actuating a restraint divestment system for instant release of a crewman equipped with a parachute and restraint harness from an aircraft ejection seat mounted restraint assembly in the event of any emergency requiring such separation. In non-ejection emergencies, the mechanism effects the release of leg restraints, seat lap belt, and the disconnect couplings connecting the parachute riser and shoulder straps and survival kit to the harness so that, in the event of a surface emergency, the crewman can escape from the aircraft with his harness intact. The actuating mechanism includes a pull cord actuated bell crank mechanism which actuates the various release mechanisms and is then latched in its full release position, and an interlock which is actuated by the seat&#39;s ejection control, to prevent release of the parachute risers and survival kit thereafter, so that the system can then be utilized by a crewman for manual separation from the seat and parachute descent with his survival kit still attached to his harness.

The invention described herein was made in the course of or under acontract or subcontract thereunder, with the U.S. Department of Defense.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of our copending application Ser. No.509,253, filed Sept. 25, 1974, for "Single Point Ground Emergency SeatRestraint Divestment System," now U.S. Pat. No. 3,954,234, issued May 4,1976.

FIELD OF THE INVENTION

The present invention relates to a single-point release actuatingmechanism finding principal but not necessarily exclusive utility inconnection with restraint systems for aircraft ejection seats, such asejection seat restraint systems which incorporate crewman operateddivestment features for use in the event of a ground emergency requiringthe crewman to evacuate the aircraft in an extremely short time spanafter initially engaging the restraint system.

For a detailed description of the structure, function and operation ofan illustrative ejection seat mechanism and an illustrative parachuteharness with which the present invention is utilized, reference shouldbe made to United States Air Force Flight Manual T.O. 1F-4C-1, Aug. 15,1972, Change 2 Feb. 26, 1973, "USAF Series F-4C, F-4D, and F-4EAircraft," pages 1-67 through 1-75, 3-15 through 3-23, and FO-21, and toUnited States Air Force Technical Manual -- Maintenance InstructionsT.O. 1F-4C-2-3, Apr. 1, 1972, Change 1 -- Apr. 1, 1973, "Seat and CanopySystems, USAF Series F-4C Aircraft," pages 4-1, et seq. To the extentnecessary for a complete understanding of the ejection seat and adjunctequipment these manuals are incorporated herein by reference.

BACKGROUND OF THE INVENTION

An aircraft crewman, particularly in military aircraft, is equipped witha variety of restraint, recovery and life support systems which areprincipally utilized while the aircraft is in flight and in the event ofthe necessity for an emergency evacuation, particularly at highaltitudes from fast moving aircraft. The crewman conventionally wears aharness which fits over his back and shoulders with a chest strapconnecting the upper portion of the shoulder straps and leg straps whichwrap around the legs and thighs of the wearer. Such a harness commonlyreferred to as a parachute harness, additionally supports terminals foroxygen and communication systems, as well as coupling devices forsecuring to the harness the parachute canopy risers, shoulder restraintstraps and survival kit straps. The survival kit conventionally iscontained in the seat portion of the aircraft seat structure and, bybeing secured to the crewman's parachute harness, is retained by him inthe event of an emergency evacuation by seat ejection, followed byparachute landing. Also included in the restraint system is aconventional seat or lap belt together with leg restraints securing thecrewman's legs to the seat structure, and sticker clip straps whichreleasably secure the survival kit straps and thus the connected harnessto the seat structure.

In the event of an emergency evacuation while the aircraft is in flight,the entire ejection seat and restraint system, including the parachuteand survival kit is power ejected from the aircraft. At an appropriatetime after the seat is safely away from the aircraft, and the crewmanand seat unit is at or has descended to a safe altitude, the seatrestraints are automatically disengaged allowing the crewman to descendsafely by means of the parachute secured to the shoulder straps of hisharness and carrying with him the survival kit secured to the harness.Life support systems, particularly emergency oxygen, are carried withthe ejection system and the oxygen is supplied to the crewman's oxygenmask through the harness mounted coupling system.

As an added safety feature, in the event the automatic seat restraintdisengagement procedures are not accomplished, the aircraft seatconventionally includes manually actuated devices for releasing the seatand leg restraints allowing the seat to fall away and for performingseveral other functions so that the crewman can pull his ripcord anddescend by parachute.

After a parachute landing, under some circumstances it is desirable forthe person to quickly divest himself of the parachute harness. To thisend, parachute harness release systems have been designed, anillustrative one of which is shown in U.S. Pat. No. 3,658,281 issuedApr. 25, 1972, to J. A. Gaylord for "Single Release For ParachuteHarness." The Gaylord system releases the complete parachute harness,including the survival kit carried thereby, and is intended fordivestment of the complete parachute harness after landing from anemergency evacuation from a moving aircraft and parachute descent. Oncesafely on the ground, the wearer usually discards the parachute harness.Therefore, there is no need in the Gaylord structure to disconnect thesurvival kit from the harness proper. Further, once on the ground, thereis little if any need for a harness release system which can be quicklyreconnected should the crewman decide that he wishes to retain and wearthe harness.

It will be appreciated that once a crewman has positioned himself in anaircraft, engaged his harness with his oxygen, communication and lifesupport systems, engaged the seat shoulder straps and parachute risers,engaged the seat lap belt and leg restraints, and engaged the survivalkit straps, he is effectively integrated into and fully restrainedwithin the aircraft cockpit. There is still, however, a substantialdanger, particularly for combat aircraft, of fire or other emergencyoccurring during start-up, take-off or after landing, or while theaircraft is on the ground or water, necessitating immediate evacuationby the crewman from the aircraft. While under some circumstances it ispossible to initiate the ejection seat while the aircraft is on theground, the risk of injury by utilizing that procedure is substantial.

OBJECTS OF THE INVENTION

It is the principal object of the present invention to provide a new andimproved actuating mechanism for actuating a seat restraint divestmentsystem thereby to increase the speed of crew escape and rescue fromaircraft cockpits in ground emergencies.

Another object of the present invention is to provide a mechanism foractuating a seat restraint divestment system, which mechanism is mountedon an aircraft seat, does not affect routine procedures for coupling toor disengagement from the crewman borne harness, and which includessafety interlocks to prevent actuation of the parachute and survival kitreleases after initiation of ejection from an aircraft in flight.

A further object of the present invention is to provide a mechanism foractuating a seat restraint divestment system which is safe and reliablein operation, is simple to install and utilize, is economical andfacilitates field installation.

A more specific object is to provide a mechanism for actuating arestraint divestment system which requires a single motion, precludesinadvertent actuation as well as disconnection from the parachute andsurvival kit after initiation of ejection, and does not compromiseparachute and restraint system integrity.

Other objects and advantages of the present invention will becomeapparent from the following description of the preferred embodimenttaken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

In accordance with the foregoing objects, the present invention isembodied in a mechanism for actuating a restraint divestment system forreleasing a crewman equipped with a parachute and restraint harness froman aircraft ejection seat and seat mounted restraining assembly in theevent of a ground emergency. After entering the aircraft cockpit andconnecting the various restraint systems, it is desirable that thesystems be releasable by a single manipulation of a release control sothat the crewman may escape from the aircraft rapidly in the event of aground emergency. To this end, the couplings between the crewman'sharness and the parachute risers, shoulder restraints and survival kitare formed of quick disconnect couplings. The seat mounted releasedevices for the lap belt and leg restraints are utilized. All of therelease mechanisms are actuated by the mechanism which includes a pullcord operated bell crank device having various bell crank arms connectedto initiating devices for releasing the restraints. Appropriate lostmotion connections are utilized so that the restraints are sequentiallyactuated thereby reducing the force of the pull required on the pullcord, and effecting actuation of the various release devices in thedesired sequence.

The quick disconnect couplings connecting the crewman's harness to theparachute riser and shoulder restraints as well as the survival kitstraps are actuated by any suitable positive pressure source such as hotgas rapid deflagrating cord. An interlock is also provided in the rapiddeflagrating cord firing device to prevent actuation of the firingdevice in the event of an in-flight ejection. The cord sections leadingto the harness connected disconnect couplings are coupled to theejection seat by appropriate pull-away swivel fittings so that incircumstances when the interlock has prevented actuation of thesepowered disconnect couplings, the cords are readily pulled away from theseat allowing a free and clear separation between the seat and thecrewman for parachute descent. The restraint divestment system andadjunct equipment thus afford a high safety factor allowing immediateescape from the aircraft in the event of a surface emergency as well asadapting the system for use in separation from the seat withoutdisconnecting the parachute or survival kit in the event of an emergencyescape from a moving aircraft.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view illustrating a restraint divestment systemutilizing the present invention in relationship with an aircraftejection seat and harness.

FIG. 1a is an isometric view illustrating diagramatically a parachuteharness with a survival kit and portions of parachute canopy riserssecured thereto.

FIG. 2 is a front view of the upper portion of the system shown in FIG.1.

FIG. 3 is a left-hand side view of a portion of the system shown inFIGS. 1 and 2.

FIG. 4 is a front view, partially schematic, of the system shown inFIGS. 1 and 2.

FIG. 5 is an enlarged elevation view of the release mechanism embodyingthe present invention and forming a part of the assembly shown in FIG.1.

FIG. 6 is a front elevation view of the mechanism shown in FIG. 5.

FIG. 7 is an enlarged section view taken substantially in the plane ofline 7--7 on FIG. 6.

FIG. 8 is an enlarged section view taken substantially in the plane ofline 8--8 on FIG. 5.

FIG. 9 is an enlarged section view taken substantially in the plane ofline 9--9 on FIG. 6.

FIG. 10 is a section view of a quick disconnect fitting for use withpressure conduit such as rapid deflagrating cord.

FIG. 11 is a view similar to that of FIG. 5 but with the pull cordpulled to the end of the lost motion stroke.

FIG. 12 is a view similar to FIG. 11 but showing the mechanism afterfurther movement of the pull cord.

FIG. 13 is a view similar to that of FIG. 11 but showing the mechanismafter a still further movement of the pull cord.

FIG. 14 is a view similar to that of FIG. 11 but showing the mechanismafter the pull cord has been pulled to its full extent.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention constitutes a mechanism for single-pointcontrolled actuation of a restraint divestment system for releasing acrewman equipped with a parachute and restraint harness from an aircraftejection seat. While portions of one illustrative ejection seat andharness have been shown in the drawings, and will be described briefly,such equipment is shown in substantial detail in the above-referencedmanuals. Moreover, the particular seat and harness structures may varyaccording to the particular aircraft or equipment manufacturer'sspecifications. In general, the harness is basically intended as aparachute harness for supporting the crewman in the event of anin-flight ejection or bailout from the aircraft. The harness does,however, serve for attachment of upper torso restraints, includinginertia reel connected shoulder straps, and to support a survival kitfor the crewman's use after landing from a bailout, and in additionsupports connections for his oxygen mask system and possibly forcommunication and life support systems.

The ejection seat may also take a variety of forms, depending upon theparticular manufacturer. Essentially, the seat both supports the crewmanduring flight and serves as his means of emergency egress from theaircraft in an in-flight emergency. In such event, the entire seatcarrying the crewman and his parachute is ejected from the aircraft bycatapult, usually augmented by rocket propulsion. At an appropriate timeafter ejection, such as when the seat and crewman have descended to asafe altitude, the seat automatically separates from the man and hisparachute, the parachute opens and he is lowered safely to the ground.In the event the seat separation system does not function properly, themanual release mechanism embodying the invention can be activated sothat the man can separate himself from the seat and manually actuate theparachute ripcord mechanism.

Referring to FIG. 1. of the drawings, an illustrative ejection seat andparachute harness and survival kit are there shown in the juxtaposedconfiguration normally encountered when a crewman is seated in theaircraft cockpit and has engaged the various restraints in preparationfor takeoff. The harness, indicated generally at 20, is formed byshoulder strap portions 21 which extend up the back and over theshoulders of the wearer, and leg portions 22 which extend down the backfrom the shoulder portions and around the thighs to a point on the frontof the torso where they connect with the shoulder strap portions. Achest strap 23 connects the two shoulder portions 21. At a point abovethe chest strap 23, the shoulder straps 21 of the harness are connectedby fittings 25 to parachute riser straps 26 and seat mounted shoulderrestraints 27. At a point on the harness adjacent to the terminals ofthe leg straps 22 the harness is connected by fittings 29 to survivalkit straps 30. The harness 20 may also carry an oxygen supply fitting 31through which the crewman connects his oxygen mask hose (not shown) bymeans of a bayonet fitting and to which is connected both the mainaircraft oxygen hose (not shown) and the emergency oxygen hose (notshown), which hoses are in turn connected with the aircraft andemergency oxygen supplies respectively with readily releasable frictionfittings (not shown) in a conventional manner.

In the event of a ground emergency, it is generally desirable for thecrewman to retain his harness as he scrambles from the cockpit. If anemergency escape system provides for separating the harness, there isalways the danger that the harness will remain connected to the oxygenmask and thus become a drag on the man as he leaves the cockpit. Aharness release system which severs or otherwise releases the harnessstraps so that a man may divest himself of his parachute after havingsafely landed following an ejection may, however, be incorporated on theharness and would serve as a backup system to the system embodying thepresent invention.

The shoulder harness and parachute riser fittings 25 are preferably ofthe type shown in U.S. Pat. No. 3,872,556, issued Mar. 25, 1975 to R. H.Frost, for "Gas Operated Quick Disconnect Coupling." Such fittingsinclude a manually releasable female section 33, shown in the drawingsmounted on the shoulder strap portion 21 of the harness 20, and a powerreleasable male section 34 coupled to the parachute riser 26 andshoulder restraint strap 27. An illustrative power releasable malefitting section 34 is described in detail in the above-mentioned patentand as described in said patent, is actuated by fluid pressure,preferably by a hot gas energy transfer system, commonly known as arapid deflagrating cord, one form of which is available commerciallyunder the trademark "Hivelite" from Teledyne McCormick Selph Company ofHollister, Calif. Igniting the cord material at one end causes an almostinstantaneous burning of the deflagrating material contained by the cordto ignite a boost charge at the terminals to produce sufficient hot gaspressure to disconnect the coupling at the male member 34. Rapiddeflagrating cord thus finds particular utility where it is necessarythat it be actuated at a point remote from the location at which it isdesired to obtain work from the hot gas, and yet achieve almostinstantaneous action at the work point. Alternative pressure producingsystems may be used to advantage without departing from the presentinvention.

The survival kit fittings 29 are also quick disconnect couplings, bututilize as the male portion a ring, such as a V-ring 36, secured to theharness on each side thereof adjacent the leg straps 22. The V-ringlatch members 36 couple with quick disconnect female couplings 37secured to the survival kit straps 30. The quick disconnect couplingmembers 37 are also actuated by a suitable remote pressure sourcemechanism such as rapid deflagrating cord 38 connected thereto. Both therapid deflagrating cord transfer lines 35 to actuate the shoulderharness and parachute riser fittings 34 and the rapid deflagrating cordtransfer lines 38 to the survival kit fittings 37 may be in turnactuated from a master cord 39 connected thereto by appropriate fittingswhich will be described in somewhat more detail below, so that all ofthe quick disconnect couplings are actuated substantially simultaneouslyupon the ignition of the master cord 39 by an appropriate firing charge.

The aircraft seat, indicated generally at 40, serves the dual functionof supporting and retaining the crewman during flight operation as wellas an escape system for emergency ejection from the aircraft. The seat40, which will sometimes be referred to as an ejection seat, isdescribed in detail in the above-referenced manuals. Referring to FIG. 1of the drawings, the ejection seat 40 includes a back section 41supporting a parachute 42 and a back rest cushion or lumbar pad 43. Theparachute is connected to the crewman's harness at the fittings 25through the risers 26. Inertia reel and straps (not shown) mounted onthe seat back 41 connect the shoulder straps 27 to the seat. Thus, byreleasing the fittings 25, the harness and upper torso of the crewman'sbody are released from the parachute risers 26 and shoulder restraints27.

The seat bucket or base 44 carries a spacer or cushion which is formedby a survival kit 45 having an upper padded surface. The survival kit 45is releasably secured to the seat bucket 44 by hold down straps (notshown) and sticker straps 46 releasably secured to the seat bucket 44engage the survival kit straps 30. The seat base 44 also carries a lapbelt 48 and releasable leg restraints 49. The lap belt is releasableboth by manually uncoupling its buckle and automatically at its pointsof connection with the seat structure 44. In the latter regard, the lapbelt 48 is secured at each of its ends on the seat bucket 44 by anappropriate release mechanism such as a latch 50. The leg restraints arelikewise secured to the seat bucket by releasable latches 51. The lapbelt is secured over the lap of the crewman by connecting the inner endsthereof together with an appropriate buckle 52, while the leg restraints49 include garters and buckles 54 for engaging the calves of thecrewman. Additional garters and buckles (not shown) may be included toengage the crewman's thighs.

While the ejection seat includes a variety of other accessories asdescribed in the above-referenced manuals, the foregoing restraintelements are those which, when engaged by the crewman, not only protecthim and restrain him during violent maneuvers or deceleration of theaircraft, but also delay or hinder his egress from the cockpit except inthe event of the actuation of the ejection seat. Thus, after the crewmanhas entered the aircraft cockpit and engaged the various restraintdevices described above to himself and his parachute harness, he mustdisengage the restraint devices before he can leave the cockpit.

The present invention is embodied in a new and improved single pointrelease mechanism, actuation of which substantially instantaneouslyreleases the crewman and his harness from the restraints allowing him toevacuate the cockpit within a few seconds in the event of a groundemergency. In accordance with the present invention, the mechanismincludes means for sequentially actuating the various restrainingdevices to enable the crewman to leave the aircraft cockpit rapidly in aground emergency. This actuating means serves to release the legrestraints, causes the canopy riser and shoulder straps to disconnectfrom the harness, effects a disengagement of the survival kit latchesfrom the harness, and disengages the lap belt from the seat bucket. Thepresent invention accomplishes this with a single point controlmechanism mounted on the seat bucket and operable by a crewman sittingon the seat during or after the process of connecting his variousrestraint devices, or by a rescuer reaching into the cockpit fromoutside the aircraft. It will be appreciated that it is not necessarythat all of the restraint devices be connected as the various releasemechanism will be activated regardless of whether or not they have beenconnected. As a further advantage of the single point release mechanismembodied in the present invention, the same mechanism may be utilized inconnection with in-flight emergency ejection and parachute descentprocedures as described in the above-referenced flight manuals. In thisregard, initial actuation of the seat ejection mechanism by the crewmaninterdicts the firing device that causes pressure or powered operationof the parachute canopy riser and survival kit release mechanism whileallowing the actuation of the leg restraint and seat belt and shoulderharness release mechanisms. The latter operation is sometimes necessaryin the event the automatic altitude release mechanisms do not operate,requiring the crewman to manually disengage himself from the ejectionseat after ejection, or manual bailout in the event ejection does notoccur, and before personnel parachute descent can be initiated.

With reference to the drawings, the single point release mechanismactuator as there shown comprises a mounting plate 60 secured on theright hand outer wall of the seat bucket 44 and carrying a pulley orsheave 61 mounted on a shaft 62 carried by the plate 60. The sheave isbiased for rotary movement in a counterclockwise direction by a clockspring 64 which acts to rotate the sheave 61. The sheave is providedwith a circumferential channel 65 which carries a cable 66 extendingaround a substantial portion of the periphery of the sheave, and thenupwardly through a guide bracket 68 where it is connected with aflexible rubber pull handle 69 positioned for convenient access by acrewman in the seat 40. By pulling on the handle 69, the cable 66effects rotation of the sheave 61 in a clockwise direction.

In order to prevent accidental operation of the release mechanism, andto insure that the handle is only intentionally pulled, initial movementof the handle and cable is restricted to require a breakout force whichin the present embodiment is approximately in the amount of 30 pounds.To this end, the cable guide housing or bracket 68 defines a chamber 70in which is rotatably mounted a shaft 71 carrying a double pronged latchdog 72. The dog is biased for rotation in a clockwise direction by aheavy torsion spring 74, and one prong of the dog 75 includes a camsurface 76 engagable by a pin 78 on the peripheral wall of the sheave61. The torsion spring force, combined with the angle of the camsurface, determine the initial breakout force which must be overcome bythe handle in order to pull the pin 78 past the prong 75 of the latchdog to free the sheave for rotation.

When the handle 69 has been pulled with sufficient force to turn thesheave 61 a distance sufficient to allow the pin to clear the firstprong 75 of the latch dog, the dog is rotated by the torsion spring 74,in a clockwise direction, to a point where the first prong 75 engages astop shoulder 79 defined on the latch housing. At that point, the secondprong 80 of the latch dog 72 extends downwardly out of the latch housingcavity 70 where it serves as a latch, as will be described below. Whenthe sheave 61 has rotated a distance sufficient for the pin 78 to clearthe latch dog, the pulling force required is substantially decreased.Depending on the location of the pin 78 on the sheave, a lost motion arcis provided during which no releases are actuated.

For actuating the various release mechanisms, the sheave shaft 62rotatably supports a bell crank spider 82. In the embodiment shown, thebell crank 82 includes four arms, three of which are coupled toappropriate release actuating linkages, and the fourth of which 84includes as inturned finger 85 adapted to be engaged by a lug 86 on thesheave after the sheave has rotated through a lost motion arc. Thedistance between the point at which the pin 78 clears the latch dog 75and the point where the lug 86 engages the bell crank finger 85determines the amount of lost motion in the actuating handle 69 andcable 66. This lost motion insures that actuation of the restraintrelease mechanism is intentional and further prevents unintended oraccidental actuation such as, for example, might be caused by steppingon the actuating handle 69.

Referring in more detail to the bell crank 82, one arm 88 thereof iscoupled by a one-way push link 89 to one leg 91 of a second bell crank90. The bell crank 90 is fixed on a shaft 92 which in turn is connected,by an appropriate linkage 94, to the seat belt release latches 50, andthe inertia reel strap terminal release, (not shown). A second leg 95 ofthe bell crank 90 is secured through a link 96 to release latches 51 forreleasing the leg restraints from the bucket 44.

For releasing the parachute riser and shoulder restraint disconnectcouplings 25 together with the survival kit couplings 29, another arm 99of the bell crank 82 is coupled to a rapid deflagrating cord firingmechanism 100 by means of a pin 101 on the arm 99 slidingly engaged witha lost motion link 102 which is, in turn, secured to the end of a firingpin actuating link 104. The main or master rapid deflagrating cord 39 iscoupled to the firing mechanism 100 by an appropriate fitting 105 whichincludes a primer or firing cap 106 located to be struck by a firing pin108, carried by a spring biased plunger 107. The firing pin is cockedagainst the force of the spring 109 as the pin 101 lifts the link 102.When the link 102 has been lifted sufficiently to allow a latch 110 toslip away from the firing pin plunger, 107 the firing pin, under theforce of the spring 109, strikes the cap 106 and ignites the rapiddeflagrating cord. The cord burns rapidly through the master cord 39 tothe various fittings and junctions and branch cords 35 and 38 which leadto the various hot gas actuated disconnect devices.

In the event the ejection seat is actuated in the usual manner during anin-flight emergency, either through pulling the ejection seat D-ring infront of the seat or pulling on the face curtain located above thecrewman's head, it is essential that the parachute riser disconnect andsurvival kit disconnect devices be prevented from actuation because ofthe disastrous consequences ensuing therefrom. To this end, the rapiddeflagrating cord firing housing includes an interdict device 112 bymeans of which an interdict pin 114 is positioned beneath the firing pinbody or plunger 107 to prevent the firing pin 108 from hitting thefiring cap 106. The interdict device is actuated by a cable 115 securedto a crank on the conventional torque tube 116 forming a part of theseat ejection control mechanism. The torque tube is initially rotated byactuation of either the face curtain or the D-ring, and prior to actualejection. In response to the resultant pull on cable 115, the safety pin114 is released and driven by a spring 118 into interdicting positionwith the firing pin plunger 107.

When the safety pin 114 interdicts the firing pin plunger 107 therebypreventing actuation of the hot gas actuated disconnect devices, thesingle point system as described can be utilized for manualdisengagement from the ejection seat in the event the altitude sensingand timed automatic release mechanism fails to operate. In this mode, itis further necessary that the personnel parachute withdrawal line besevered from its connection to the drogue chute to allow the former tobe activated by a ripcord. Accordingly, a third arm 120 on the bellcrank 82 is connected, through a link 121 and bell crank 122, to aguillotine or cutter initiating mechanism 124. The guillotine or cuttersevers the personnel parachute withdrawal line between the drogueparachutes and the personnel parachute and its pack. The seat occupantthen pushes free of the seat and the sticker clips that hold him and hissurvival kit to the seat, and when free pulls the parachute ripcord andmakes a normal parachute descent to the ground.

In either the surface emergency escape mode or the manual seatseparation or ejection mode, a continued pull on the release mechanismhandle 69 to full release position causes the sheave 61 and bell crank82 to continue to rotate until the arm 99 is engaged by and latchesunder the second prong 80 of the latch dog 72. When so latched, all ofthe bell crank linkages are held in the release position as the cablerewinds on the sheave. This insures that the seat belt and leg restraintlatches cannot re-engage even though the crewman does not immediatelypull himself free of these restraints.

The actuating mechanism effects, by a single point actuation, a multiplepoint release thereby enabling a crewman to free himself of allrestraints and escape from the aircraft in the shortest possible timespan when confronted by a ground emergency. It will be appreciated that,upon exiting the aircraft with his harness intact, the various oxygen,communication and life support lines which may be coupled to the crewmanor his harness are designed to quickly and easily pull free of the seatand aircraft attachment leaving the man unrestrained by any connectionto the seat or aircraft. With the device as described, it is necessaryfor the crewman to actuate only one mechanism with a single movement. Bysafetying the mechanism in the event of an attempted seat ejection, thesame release movement and mechanism may be simply and effectivelyutilized in the event of an automatic seat disengagement or ejectionfailure thereby allowing manual separation from the seat and actuationof the parachute for a safe descent from an in-flight emergencynecessitating escape.

The hot gas rapid deflagrating cords connect to pull away fittings whichenable the portions of the cords connected to the parachute risers andsurvival kit straps to be pulled away from interconnection with themaster cord at the point of connection with the seat. An illustrativepull away fitting is shown at FIG. 10 in the drawings and comprises afitting body 130 having a central cavity 131 adapted to removablyreceive a fitting nipple 132. The nipple 132 is held in the fitting bodyby a detent 134 which, as shown in the drawings, comprises a ball detentmember 135 spring biased by a plurality of Belleville springs 136 into agroove 138 formed in the exterior surface of the inserted end of thefitting nipple 132. The body chamber 131 is vented to the atmospherethrough a vent 139 in the bottom thereof. A plurality of passages 140through the body 130 open into the central chamber 131 through aninternal annular groove 141 formed in either the external surface of thenipple or the internal surface of the fitting body, but preferably inthe latter and not both. In the modification illustrated, the annulargroove is shown as formed in the fitting body. The nipple 132 is formedwith a blind axial passage 142 extending partially therethrough andterminating in a plurality of transverse passages 144 which open intothe exterior wall of the nipple 132 at a point coinciding with theannular groove 141 in the fitting body. The nipple 132 is furtherprovided with spaced O-ring seals 145 on either side of the transversepassage 144 and the annular groove 141 to prevent the leakage of fluidsuch as hot gas from the body around the nipple. Both the nipple and thefitting body include appropriate threaded connecting means at the outletend of the various passages 142 and 140 respectively, by means of whichconduits, such as rapid deflagrating cord, may be secured and sealed tothe fitting. As shown, the fitting body 130 includes internally threadedcounterbores 146 for receiving externally threaded fittings 147 on therapid deflagrating cord. Similarly, the axial passage 142 of the nipple132 terminates in an internally threaded counterbore 148 for engagementwith an externally threaded fitting 149 on a rapid deflagrating cord orother such conduit. The fitting body further includes appropriatemounting structures, such as an apertured ear 150, by means of which thebody can be rotatably mounted on the seat or other structure in order toprovide a self-aligning directional pull release. It will be appreciatedthat the nipple can be readily inserted into or withdrawn from thefitting body, the force required being determined by the detent 134.

While a certain illustrative embodiment of the present invention hasbeen shown in the drawings and described in considerable detail, itshould be understood that there is no intention to limit the inventionto the specific forms disclosed. On the contrary, the intention is tocover all modifications, alternative constructions, equivalents and usesfalling within the spirit and scope of the invention as expressed in theappended claims.

We claim:
 1. A single point actuating mechanism for use in sequentiallyactuating a multiple unit system, comprising in combination, a rotaryrewind spring biased cable driven sheave having a pull cable securedthereto and terminating in a pull handle, a stiffly releasable detentmeans engaging said sheave for initially restraining said sheave againstunintended rotation, a rotatable multi-armed bell crank mounted forcoaxial rotation with respect to said sheave, lug means on said sheavefor operative driving engagement with said bell crank after partialrotation of said sheave, link means operatively coupling said bell crankarm to selected units of the system to be actuated as said bell crank isturned by said cable driven sheave, and said detent means engaging andlocking said bell crank to positively hold said bell crank in its fullyrotated position upon completion of the pull on and subsequent releaseof the pull handle.
 2. The actuating mechanism as defined in claim 1wherein at least one of said link means includes a lost motionconnection.
 3. The actuating mechanism as defined in claim 1 whereinsaid detent means comprises a pivotally mounted latch dog, a torsionspring biasing said dog toward detent position, and a pin on said sheaveengageable with said dog and acting thereon in opposition to saidtorsion spring to provide a resistive release to the rotation of saidsheave.
 4. The actuating mechanism as defined in claim 3 wherein saiddog is pivoted by said torsion spring after release from said pin to asecond detent position for locking engagement with one arm of said bellcrank.
 5. The actuating mechanism as defined in claim 1 wherein saidbell crank and said sheave are coaxially mounted for rotation on acommon shaft, and said bell crank includes an arm having an inturnedfinger for engagement by the lug means on said sheave.
 6. An actuatingmechanism as defined in claim 1 further including a firing mechanism forigniting a rapid deflagrating cord comprising, in combination, a tubularhousing, means at one end of said housing for receiving the ignition endof a rapid deflagrating cord, a firing pin slideably mounted in saidhousing for operative engagement with said ignition end, a spring fordriving said firing pin into igniting relationship with said ignitionend, means for releasably holding said firing pin in cocked position,and means coupling said releasably holding means to said bell crank forreleasing said firing pin in response to rotation of said bell crank bysaid pull cable driver sheave.
 7. An actuating mechanism as defined inclaim 6 wherein said coupling means includes a lost motion mechanism. 8.An actuating mechanism as defined in claim 6 including means mounted onsaid housing for interdicting said firing pin to prevent said pin fromengaging said ignition end in response to a previous predeterminedcondition of said multiple unit system.
 9. An actuating mechanism asdefined in claim 8 wherein said interdicting means comprises a lateraltubular member integral with said housing, an interdict pin slidablymounted in said tubular member, means biasing said pin into interdictposition relative to said firing pin and means for releasably holdingsaid pin within said tubular member and out of interdict engagement withsaid firing pin.
 10. An actuating mechanism for sequentially actuatingeach unit of a multiple unit system, comprising in combination, a basehaving a central shaft therein, a rotary sheave mounted for rotation onsaid shaft, a rewind spring operatively coupled between said base andsaid sheave for biasing said sheave for rotation in one direction, apull cable secured to said sheave and wrapped around the peripherythereof for rotating said sheave in a direction opposite to the biaseffected by said spring, said pull cable terminating in a pull handle,means on said base for guiding said cable and for engaging andsupporting said handle for limiting rotation of said sheave in said onedirection, a stiffly releasable spring biased double acting detent meansmounted on said base and engaging said sheave for initially restrainingsaid sheave against unintended rotation in said opposite direction, arotatable multi-armed bell crank mounted on said shaft for coaxialrotation with respect to said sheave, lug means on said sheave foroperative driving engagement with said bell crank after partial rotationof said sheave in said opposite direction effected by a pull on saidhandle and release of said detent means, link means operatively couplingsaid bell crank arms to selected units of the system to be actuated assaid bell crank is turned by said sheave, and means on said bell crankfor operatively engaging said detent means to lock said bell crank andpositively hold said bell crank in its fully rotated position uponcompletion of the rotation of said sheave in said opposite direction andsubsequent release of the pull handle and rotation of said sheave insaid one direction.
 11. A single point actuating mechanism for use insequentially actuating a multiple unit system comprising in combination,a rotary rewind spring biased sheave, means secured to said sheave forrotating the same in opposition to said spring bias, first detent meansoperatively engaged with said sheave for initially restraining saidsheave against unintended rotation, bell crank means mounted for coaxialrotation with respect to said sheave, means on said sheave for operativedriving engagement with said bell crank after partial rotation of saidsheave, means operatively coupling said bell crank arms to selectedunits of the system to be actuated as said bell crank is rotated inresponse to rotation of said sheave, and second detent means forengaging and locking said bell crank to positively hold said bell crankin its fully rotated position upon completion of the rotation of saidsheave.
 12. The actuating mechanism as defined in claim 11 wherein atleast one of said operative coupling means includes a lost motionconnection.
 13. The actuating mechanism as defined in claim 11 whereinsaid first detent means comprises a pivotally mounted detent dog, atorsion spring biasing said dog into detent position, and a pin on saidsheave engageable with said dog and acting thereon in opposition to saidtorsion spring to provide a resistive release to the rotation of saidsheave.
 14. The actuating mechanism as defined in claim 13 wherein saiddog is pivoted by said torsion spring after release from said pin to asecond detent position comprising said second detent means for lockingengagement with said bell crank.